System and apparatus for sound-attenuation of gas streams



May 21, 1963 F. E. DEREMER 3,090,454

SYSTEM AND APPARATUS FOR SoUND-ATTENUATTON 0F GAS STREAMS Filed Aug. 8, 1958 2 Sheets-Sheet 1 /0 54 446 55 52 36 iiir1 Y /5 74 glzi l l I-/ff 25 dil: ilnl /4 "Il: iiLt l W 20 HH Z4 47 57 54 ZZ /Z E00 55 l'/ ATTORNEY May 21, 1963 F. E. DEREMER SYSTEM AND APPARATUS FOR SOUND-ATTENUATION OF GAS STREAMS 2 Sheets-Sheet 2 Filed Aug. 8, 1958 INVENTCR: FL @YD E. DEREME'R.

A .T wm uw mwen 'w W ATTORNEY United States Patent Office 3,090,464- Patented May 21, 1963 3,699,464 SYSTEM AND APPARATUS FR SOUND-ATTENU- ATIUN F GAS STREAMS Floyd E. Deremer, Livonia, Mich., assigner to @ldherg Manufacturing Company, Grand Haven, Mich., a corporation of Michigan Filed Aug. 8, 1953, der. No. 753,984 6 Claims. (Cl. Mlm-57) This invention relates to a sound-attenuating system and apparatus particularly adapted for use with the exhaust gas stream or streams from an internal combustion engine of an automotive vehicle and more particularly to an exhaust gas conveying arrangement and a gas blending and sound-attenuating means for attenuating sound waves entrained in the gas streams.

At the present time the trend in the development and manufacture of automotive vehicles is a more extensive use of multi-cylinder engines particularly of the type embodying two parallel banks of cylinders such as an eight cylinder engine with four cylinders in each bank, an individual exhaust manifold being employed with each bank of cylinders and two or more sound-attenuating means or mulilers embodied in the exhaust duct arrangements accommodating the gas streams issuing from the exhaust manifolds.

The use of multi-cylinder engines wherein the cylinders are arranged in banks augments the difficulties of conveying the exhaust gases from the engine and providing apparatus which will satisfactorily attenuate or dampen objectionable sound waves in the exhaust gas streams without appreciably increasing back pressure in the exhaust gas ducts and sound-attenuating means.

Another factor inuencing the use of exhaust gas manifolding or conveying means for each bank of cylinders and a plurality of sound-attenuating means is the trend toward substantial increase in the horsepower of the engines which necessarily involves an increased volume of exhaust gases to be disposed of and sound waves of the gas streams attenuated. A single mulller in each stream in order to satisfactorily attenuate sound waves would have to be of substantial length.

The trend in vehicle design toward lowering of the frame construction of the vehicle requires an increase in the number of reinforcing cross members in the frame construction for proper strength, and the space beneath the vehicle body to accommodate a single sound-attenuating muffler means of a length adequate to properly attenuate the sound waves is inadequate. Hence automotive vehicle manufacturers have, in many installations, employed additional resonators or supplemental soundattenuating mufers arranged in series in each of the exhaust gas conveying means from the individual manifolds of the engine as an expedient to attenuate sound waves over the objectionable wave range.

Sound-attenuating systems of this character are costly because `of the number of muilers and resonators required. As the resonators 'are spaced rearwardly of the muiliers in each exhaust gas duct arrangement, there is a definite tendency for moisture condensation to form in the resonators as the temperature of the exhaust gases in the resonators is substantially reduced due to their remote positioning from the engine. Moisture causes rapid oxidation or rusting of the metal of the resonator units and in a short period of time must be replaced.

The present invention embraces the provision of an exhaust gas conveying and sound-attenuating system especially adapted to receive and accommodate multiple exhaust gas streams wherein a single muffler unit or sound-attenuating unit is disposed transversely of the vehicle and forwardly of the engine whereby the exhaust pipes or tubes of comparatively short length may be employed for conveying gases from the engine manifolds to the sound-attenuating muiiler or unit.

The invention embraces a system and apparatus for attenuating sound waves entrained in multiple exhaust gas streams from an internal combustion engine in a single unit or muffler disposed to accommodate the exhaust gas streams from both banks of cylinders of an engine Lwithout objectionable back pressure.

Another object of the invention resides in the provision of a sound-attenuating apparatus or muffler of a character particularly adapted to be disposed or positioned transversely of a vehicle and forwardly of the internal combustion engine or prime mover and adapted to accomodate multiple exhaust gas streams from multiple banks of engine cylinders wherein the exhaust gases are admitted into the ends of the sound-attenuating apparatus in a manner wherein a blending `of the gases of the streams is effected within the sound-attenuating means and eiicient sound-attenuation obtained and the spent exhaust gases discharged from the sound-attenuating unit or muiiier through one or more outlets.

Another object of the invention is the provision of a sound-attenuating system for an internal combustion engine of an automotive vehicle wherein sound waves throughout the objectionable sound wave range of the exhaust gas stream or streams may be satisfactorily attenuated within a single mufer or sound-attenuating unit whereby the cost of sound-attenuating apparatus for exhaust gas systems is substantially reduced over prior systems.

Another object of the invention is the provision of an exhaust gas disposal system and attenuating apparatus for exhaust gas streams of a vehicle engine wherein secondary sound-attenuating means o-r resonators are eliminated without the sacrilice `of proper sound-attennation.

Another object of the invention is the provision of a single unit intercalated in an exhaust gas system of nn internal combustion engine for blending multiple exhaust gas streams from banks of cylinders of a multicylinder engine wherein pressure impulses in the exhaust gas streams of irregular occurrence are blended together to smooth out the pressure impulses and effectively attenuate sound waves entrained in the streams.

Another object of the invenion is the provision of a combined gas blending and sound-attenuating unit particularly adapted for installation forwardly of the engine adapted to receive dual exhaust gas streams from the engine, the unit being provided with gas passage means in transverse spaced relation, the walls of the gas passage means being formed with openings or open areas providing acoustic couplings with suitable chambers for attenuating sound waves and facilitating transverse flow and blending of exhaust gases which are discharged from the unit through one lor more outlets adjacent the front wheels of a vehicle.

Further objects .and advantages are within the scope of this invention such las relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features las will be apparent from a consider-ation of the specication and drawing of a form of the invention, which may be preferred, in which:

FIGURE l is a schematic plan view of an automotive vehicle illustrating the exhaust system embodying a form of combined lgas blending and sound-attenuating unit of the invention arranged forwardly of the engine of the vehicle;

FIGURE 2 is a schematic elevational view of the arrangement illustrated in FIGURE l;

FIGURE 3 is a schematic partial plan View illustrating the system embodying another form of combined gas blending and sound-attenuating unit of the invention;

FIGURE 4 is a longitudinal sectional view of the combined gas blending `and sound-attenuating unit of the invention;

FIGURE 5 is a transverse sectional View taken substan-tially on the line 5 5 of FIGURE 4;

FIGURE 6 is a longitudinal sectional view showing 'another form of combined gas blending and sound-attenuating unit of the invention provided with a single exhaust gas outlet, `and FIGURE 7 is a schematic sectional view illustrating another form of combined gas blending and sound-attenuating unit of the invention.

The invention has particular utility with the exhaust gas system of a multi-cylinder engine of the type embodying parallel banks of cylinders such as an eight cylinder engine with four cylinders in each bank rwherein the combined gas blending land sound-attenuating unit is disposed forwardly of the engine and extends longitudinally in a direction transversely of the vehicle. A separate or independent exhaust manifold is provided to accommodate exhaust gases from each bank of cylinders and `the manifolds are connected respectively with the ends or end regions of the gas blending and sound-attenuating unit and the exhaust gases discharged from the unit through one or more outlets at a region adjacent one or both front wheels `of the vehicle or the exhaust gases may be conveyed by suitable means to the rear of the Vehicle for discharge to the atmosphere.

The conventional eight cylinder engine comprises two banks of cylinders arranged in parallel lengthwise of the Vehicle and the pistons are connected to a single crankshaft. Such arrangement does not permit of successive tiring cylinders alternately from each bank of cylinders throughout a tiring cycle of the eight cylinders.

During a complete cycle of tiring of all eight cylinders of the engine, there are two periods wherein the combustible mixture charges of two cylinders of one bank are tired or ignited in succession and two cylinders of the opposite bank red in succession, the others being alternately tired from opposite banks. This condition results in two exhaust impulses in succession in one manifold and two exhaust impulses in succession in the opposite manifold, while the yother four cylinders are `red in alternate relation from each bank. rhe irregular exhaust impulses in each manifold, where the exhaust is conducted through a conventional muler, causes a throbbing or pulsing sound which is not satisfactorily attenuated or mutfled. The exhaust gas system of the present invention includes a combined gas blending and sound-attenuating unit positioned forwardly of the engine and preferably adjacent the front bumper extending transversely of the vehicle and which is of `a length wherein sound-attenuation over the objectionable sound wave range may be had in a single unit and the irregular exhaust pressure impulses equalized within the unit.

With particular reference to FIGURES 1 and 2, the outline of a top plan vierw of a vehicle body is illustrated -at l@ carried or mounted upon a suitable frame structure (not shown) the vehicle being equipped with front and rear bumpers designated respectively l2 and t4. Supported at the forward region of the frame structure of the vehicle is an internal combustion engine lo of the eight cylinder type having two banks or blocks of cylinders designated 1S and Ztl respectively, each bank containing four cylinders. The vehicle is equipped with a steering wheel 22 and front seats diagrammatically illustrated at 24.

The engine 1S is connected through suitable transmission or speed change mechanism (not shown) contained within a housing 26 arranged to be connected to the rear vwheels 2S of the vehicle for driving the same in a conventional manner. The vehicle is equipped with conventional front wheels rthe bank of cylinders 18 is provided with an exhaust manifold .32 having four branches connected with the exhaust openings in the engine block or bank llt and through which the exhaust gases from the cylinders in block 18 are delivered into the manifold 32. A manifold substantially identical with manifold 32 is provided for conveying exhaust gases from the cylinders in the block 2t?.

Disposed forwardly of the engine r6 and adjacent and rearwardly of the bumper i2, is a combined gas blending and sound-attenuating unit or muier 36 supported by suitable means (not shown), the muler 36 being illustrated in further detail in FIGURE 4. As shown in FGURE 1, the muler or gas blending and attenuating unit 36 is of substantial length and, within the limitations of khe width of the vehicle, may be made of a length of lthree feet or more to provide for the attenuation of a broad range of sound waves entrained in the exhaust gas streams from the manifolds 32 and 34'.

As shown in FIGURE 4, the gas blending and soundrattenuating unit 36 is inclusive of a shell 33 which is preferably of oval or ovoidal shape in cross-section as shown in FGURE 5. The shell 3S is preferably formed with a double wall which may be in the form of two sheets 40 and 42 of metal which may be joined by means of a fold or seam d4 or they may be welded together. The shell construction may be fashioned of a single sheet of metal wrapped upon itself to form a double wall. As shown in FIGURE 5 one or" the walls may be formed with longitudinally extending ridges engageable with the other wall for spacing the walls providing an air chamber between them to assist in damping or reducing shell noise.

The mutlier construction 36 is provided with end heads 4o and t7 formed Iwith peripheral ange portions i8 which embrace the ends of the shell 38 to provide fluid-tight seals or connections. Each of the end heads and 47 is formed with -a flange portion 5% defining an inlet opening adapted to accommodate a tubular inlet fitting or coupling 52. The inlet iitting 52 in the end head d6 is connected by means of an exhaust pipe Sfr and a coupling 55 with the exhaust manifold The inlet iitting 52 in the end head t7 is connected by means of an exhaust pipe 56 Iand a coupling 57 with the exhaust manifold 34. Thus the streams of exhaust gases from the manifolds 32 and 34- are conducted into the ends of the mufer 35.

The muider 36 is formed interiorly with gas passage means and transverse partitions or walls forming chambers, the latter being in communication with gas passage means for blending exhaust gases owing into and through the muffler and concomitantly attenuating sound waves entrained in the exhaust gas streams. As shown in FIG- URE 4, there is aligned with the inlet fittings 52 a gas passage means or tube dit which, in the embodiment illustrated, extends lfull length of the muifler and receives and accommodates both exhaust gas streams from the engine.

Disposed within the mufer shell and extending transversely of the chamber formed by the shell is a plurality of walls or partitions designated from left to right by numerals 62, 63, 64, and ed. The partition 62 is spaced from the end Wall 47 to provide a resonator chamber 68 and a similar chamber 7 G is provided between the partition 66 and the end wall 46. Surrounding the gas passage means or tube 6d is a cylindrical member or tube 72 having end portions 73 which surround the periphery of the gas passage tube di).

Disposed within and spaced lengthwise of the member 72 are secondary annular partitions or walls 74 providing a series of high frequency sound-attenuating chambers 76 for attenuating high frequency sound waves. The secondary partitions 74 may be spaced as desired to secure the most elcient attenuation of high frequency waves. The wall of the gas passage means or tube 6u is provided with a substantial number of small openings Sd which are in communication with the high frequency attenuating chambers 76 and form acoustic couplings with the chambers.

The partitions 62 through 66 deline compartments or chambers 67 which not only function as sound-attenuating chambers but also serve as gas transfer passages to facilitate the iiow of gases from the gas passage means 60 into a second gas passage means or tube 82. The wall of the cylindrical member 72 surrounding the gas passage tube 66 is provided with a substantial number of perforations or openings spaced lengthwise and peripherally of the member 72 providing means whereby the gases ow transversely through the openings 80 in the wall of the tube 60 thence through the chambers 76 and openings or perforations 84 into the chambers or transverse gas passage means 67.

The tube 82 extends substantially full length of the mufiier shell 38 through openings provided in the partitions or walls 62 through 66, the end regions of the. tube 82 being equipped with outlet fittings 86 extending through suitable openings formed in the end heads 46 and 47. As shown in FIGURE 4, the wall of the tube 82 is formed throughout its full length with a plurality of comparatively small openings 8S to accommodate the transverse flow of gases through the passages 67 into the tube or gas passage means 82.

The chambers 68 and 70 are in communication with the tube 82 by means of the openings 8S which form acoustic couplings with these chambers, the chambers serving to at tenuate sound waves of lower frequencies. It should be noted that in the embodiment illustrated in FIGURE 4, the wall portions of the inlet gas passage means 60 adjacent the resonator chambers 68 and 70 are imperforate so that all of the exhaust gases entering the inlet gas passage means 66 flow transversely through the passages or chambers arranged between the partitions 62 and 66.

The exhaust gases owing through the outlet fittings 86 may be discharged through outlet pipes 106, shown in FIGURES l and 2 which direct the gases angularly toward the roadway adjacent the front wheels of the vehicle. If desired, a tube or pipe (not shown) may be connected to each of the outlet pipes 166 and convey thel exhaust gases to the rear of the vehicle.

The system and apparatus shown in FIGURES 1, 2, 4 and 5 is as follows: During the operation of the engine, the exhaust gases `are delivered from the engine through the manifolds 32, 34 and the exhaust pipes 54 and 56 into the opposite ends of the muffler and enter the muifler through the fittings 52 into the inlet gas passage means 6th As previously mentioned, the exhaust impulses in an eight cylinder engine are nonuniform because of the nonuniform firing order. Hence the incoming pressure impulses of the exhaust gases effect a surging of the gases within the tube 60 and as the gases from the manifolds are in direct opposition in the gas passage means 60, the pressures within the tube 60 tend to be equalized and the irregular pressure impulses are smoothed out or blended within the mutller.

The gases from the engine entering the exhaust inlet gas passage means 60 move laterally or transversely through the openings 80 in the wall of the tube 6) forming acoustic couplings with the intermediate shell or tube 72 surrounding the tube 60 and spaced therefrom and high frequency sound waves are attenuated in the chambers The wall of the tube. 72 is provided with a comparatively large number of small openings 84 facilitating gas flow through openings 8S into the tube 82;. The baflies 63, 64 and 65 are each provided with four or more openings 92, shown in FIGURE 5, to facilitate lengthwise flow of the gases between the baffles 62. and 66.

Thus gases within the tube 60 may ow transversely at all regions between the battles 62 and 66 into the second gas passage means or tube 82. Thel gas passage tube 82 at the region of its passage through the chambers 68 and '70 is provided with a plurality of openings or outlets 88 6 permitting the circulation of gases through the chambers 63 and 70. The openings 88 in the wall of the tube 82 provide acoustic couplings with the chambers 68 and '70 for attenuating sound waves of lower frequencies entrained in the gases.

The baffles 62 through 66 are provided with openings defined by lianges through which extends a resonator tube 94, the ends of which open into the chambers 68 and 76 respectively. Disposed within the resonator tube 94 and approximately midway between the ends thereof is an unperforated baffle, wall or plug 96 which separates the tube 94 into low frequency resonator chambers 97 and 98. The gases flow from the tube 32 through the discharge pipes litt). The discharge pipes or outlets 16) may be bent through approximately ninety degrees as shown in FIGURE l rearwardly of the vehicle and inclined downwardly as shown in FIGURE 2 to direct the exhaust gases in a region adjacent the front wheels 30 of the vehicle for dissipation in the atmosphere. During movement of the vehicle, the rotation of the front Wheels tends to disperse the exhaust gases owing from the outlet or tail pipes 16).

hrough the foregoing described arrangement, the exhaust gases from the two banks of cylinders 18 and 20 of the engine are delivered through comparatively short pipes into the respective ends of the mutiier 36 and are blended within 4the gas passage means 6i), the gases tiowed transversely into the tube 62 thence lengthwise of the tube 32 in opposite directions for discharge through the outlet pipes lili).

The pressure impulses in the gas streams tend to be equalized and sound waves, both high and low frequency, are effectively attenuated by reason of the substantial length of the muffler. The region between the baiiies 62 and 66 provide an ample area for the transverse iiow of exhaust gases from the gas passage means 66 into the gas passage means 82 without setting up or creating appreciable back pressure within the muiiier construction.

FIGURES 3 and 6 illustrate a modified form of muifler construction adapted for mounting forwardly of the engine of a vehicle. The engine 16' shown diagrammatically in FIGURE 3 is of the same type as shown at 16 in FIGURES l and 2 and includes banks of four cylinders designated 1S and 20 which are respectively provided with exhaust manifolds 32 and 34 adapted to be respectively connected to the inlet gas passage means of a muffler through the medium of tubes S4 and 56'. FIGURE 6 is a longitudinal sectional View through the muler construction 11i) shown in FIGURE 3.

The shell construction 112 of the muiiier 110 may be of the same construction as shown in the embodiment illustrated in FIGURE 4. The shell is provided with end heads 114 and 116, the central regions of the end heads being formed with iianged openings adapted to receive coupling tubes 118 and 126 which are respectively connected with the pipes 54 and 56', shown in FIGURE 3, through which the exhaust gases from the engine are conducted into a first gas passage means or tube 122 disposed within the shell 112 and extending into the couplings 11S and 126 as shown in FIGURE 6.

Disposed within and spaced lengthwise of the shell 112 are baffles 124, 125, 126, 127 and 128, adjacent pairs of the bafiies forming chambers 13). The baiiie 124 with the end head 116 forms a resonator chamber 132 adjacent the left end of the muilier construction as viewed in FIGURE 6, and the bathe 128 forms with the end head 114 a resonator chamber 134 at the right end of the muffler construction shown in FIGURE 6.

The baffles 124 through 12% are provided with flanged openings at the central regions thereof to accommodate an intermediate shell or tubular member 136 which is spaced transversely from and preferably concentric with the gas passage means or tube 122. The space between the gas passage means 122 and the intermediate shell or tube 136 is subdivided lengthwise into compartments by means of annular members 133 which form a plurality of high frequency sound-attenuating chambers between the gas passage means 122 and the surrounding tube 136.

The region of the batile 124 adjacent the gas passage means 122 is provided with a llange 14d engaging the tube, and the baflie 123 is provided with a similar ange 141 engaging the gas passage means or tube 122 to isolate the resonator chambers 132 and 134 from communication With the space between the ltube 122 and its surrounding intermediate shell or tube 136. The wall region of the tube or gas passage means 122 between the battles 124 and 12S is provided with a plurality of comparatively small openings 142 and the wall of the intermediate shell or tube 136 is likewise provided with a large number of comparatively small openings 144.

Disposed in parallelism with the gas passage means 122 is a second gas passage means or tube 1416. The end head 114 is formed with a flanged opening to accommodate an exhaust outlet coupling or tubular member 148, one end of the tube 146 extending into the coupling 143, the other end of the tube 146 extending through a flanged opening in the balile 124 establishing communication between the interior of the tube and the resonator chamber 132. The intermediate batlles 125 through 12S are provided with flanged openings to receive and accommodate the gas passage tube 146 as illustrated in FlGURE 6.

The Wall of the region of the tube 146 between the bathe 124il and the battle 123 is formed with a large number of comparatively small openings 15d. The region of the -tube 146 between the battle 12S and the end head 114 is provided with a large number of small openings 150 for establishing communication with the resonator chamber 134.

In the form of construction shown in FIGURES 3 and 6, the exhaust gases from the manifolds 32 and 34 enter respectively through the pipes d' and 5d and couplings 118 and 121) into the respective ends of the gas passage means or tube 122.

As the gases from the two banks of cylinders ilow into opposite ends of the tube 122, pressure impulses which are unequally spaced in point of time are substantially equalized or blended Within the tube 122. The exhaust gases moving through the tube 122 dow transversely in the regions between the batiies 124 and 128 through the openings 142 in the gas passage tube 122 and the openings 144 in the intermediate shell or tube 136 transversely through the chambers 13d and the openings 151i' into the tube 146 thence outwardly through the exit coupling 143 into an exhaust conveying tube or pipe d for discharging the gases from the mutiier to the atmosphere.

Each of the bafes 125, 126 and 127 is provided with four openings of the comparable size and character illustrated at 92 in FIGURE 5. The openings in these baies provide for movement of gases lengthwise of the shell between the end bales 124 and 128. The chamber 132, in communication with the end of the gas passage tube 146, provides a resonator chamber for attenuating low frequency waves and the chamber 134 in communication with the gas passage tube 146 through the medium of the openings 150 also forms a resonator chamber for attenuating low frequency sound waves.

In the arrangement shown in FIGURES 3 and 6, the exhaust gases from the engine are blended together in the gas passage means or tube 122 and high frequency sound waves are attenuated in the chambers provided between the tube wall of the tube 122 and the intermediate shell or tube 136. Ample area for the transverse flow of gases through the muier from the gas passage means 122 to the second gas passage means 146 is provided through the large number lof openings or acoustic couplings 142, 144 and 150 whereby a minimum of back pressure is encountered by the gases in `their movement through the mufer.

The exhaust gases delivered from the muiiier through the pipe 154 may be projected toward the region of the front wheel or may be conveyed to the rear of the vehicle by means of -an extension pipe `156 shown in broken lines in FIGURE 3. It should be noted in the arrangements of FIGURES 4 and 6, the exhaust gases traverse and circulate in all regions interiorly of the muffler so as to prevent pocketing or accumulation of condensation which would tend to rust or disintegrate the mufller.

FIGURE 7 illustrates diagrammatically another form of combined gas blending and muflier construction of the invention. In this arrangement, a shell 16d which may be of the character of the shell illustrated in the forms of the invention shown in FIGURES 4, 5, and 6 is provided with end heads 162 and 164i. Extending through openings in the central regions of the end heads are coupling tubes 166 and 163 which accommodate the respective ends of a gas passage means or tube 171) extending throughout the length of the muliler shell `and adapted to convey exhaust gases into the interior of the mufer through both coupling tubes 166 and 168.

Disposed within and spaced lengthwise of the shell are transversely extending baffles, walls or partitions 172, 173, 174 and 175. The baffle 172 with the end head 164 forms a resonator chamber 177, and the baiiie 175 forms with the end head 162 a resonator chamber 17S. The battles 172 through 175 are provided with openings to accommodate an intermediate shell or tabular member 179 surrounding and spaced from the gas passage means or tube 171B. The end head 162 is provided with an opening to accommodate a tubular coupling 18d which is in registration with a second gas passage tube 182 extending through openings in the baiiles 172 through 175, the tube opening into but not extending through the low frequency resonator chamber 177.

The end head 164 is provided with an opening to accommodate a tubular coupling member 184 which is in registration with a third gas passage means or tube 186 which extends substantially parallel with the tubes 170 and 1&2 and is spaced transversely therefrom, the tube 186 extending through openings formed in the battles 172 through 175. The gas passage tube 186 opens into but does not extend through the resonator chamber 178, the latter forming a means for attenuating low frequency sound waves.

The walls of the gas passage tubes 17%, 182 and 136 at the regions between the bales 172 and 175 are formed with a large number of comparatively small openings and the intermediate shell or tubular member 179 surrounding the gas passage tube 17? is formed with `a large number of small openings. The openings in the tubes 170, 132, 179 and 186 provide acoustic couplings with the adjacent chambers and form means facilitating transverse or lateral flow of exhaust gases from the inlet exhaust gas passage means 17@ to the gas passage tubes or means 182 and 186.

In this form of construction the exhaust gases from the engine manifolds of the character shown in FIGURES l and 3 enter the gas passage tube 17d at its ends, the gases moving transversely through the openings in the gas passage tube 171? and the intermediate shell 179 enter the tubes 182 and 186 through the openings in the walls thereof. rl`he exhaust gases are discharged through the couplings 18d and 1e@ which are equipped or provided with pipes of the character indicated at 154 in FIGURE 3 for directing the exhaust gases toward the regions of the front wheels. The exhaust gases may be conveyed to the rear of the vehicle through the use `of extension tubes of the character indicated in broken lines at 156 in FIG- URE 3. The operation of the muffler shown in FIG- URE 7 is substantially the same as the other forms `of the invention, the gases entering the respective ends of the first gas passage means 17u and ow transversely into the second and third gas passage means 182 and 186 and are discharged therefrom. The muiler unit 161) is adapted to be mounted forwardly of the Vehicle engine in the same manner as shown in FIGURES l and 3.

It is apparent that, within the scope lof the invention, modifications and different arrangements may be made other than is herein disclosed, and the present ydisclosure is illustrative merely, the invention comprehending `all variations thereof.

I claim:

l. A mufiler for use with the exhaust gas streams from dual manifolds of an internal combustion engine of a vehicle, the combination of an elongated chamber having end closures, each of said end closures having an inlet opening, exhaust gas conveying pipes connecting the exhaust manifolds with the inlet openings arranged to conduct streams of exhaust gases from the engine through the openings in the end clo-sures into the chamber, a first tubular gas passage means in said cham-ber registering with said inlets adapted to receive the streams of gases entering the respective ends of the chamber whereby to blend the gases of the streams, a second tubular gas passage means disposed substantially parallel With the first gas passage means in said chamber, an exhaust gas outlet in registry with the second gas passage means, an intermediate shell surrounding said first gas passage means, the walls of the tubular gas passage means and said intermediate shell being formed with a plurality of open areas to Vaccommodate transverse fiow of gases from the first to the second gas passage means, annularly shaped means positioned within and spaced lengthwise of the intermediate shell forming a plurality of high frequency sound attenuating zones, ya plurality yof transversely arranged spaced walls in said chamber forming transverse passages through which gases flow from the first to the second gas passage means, one of said walls forming with an end closure a low frequency sound attenuating Zone, at least one of said tubul-ar gas passage means being in communication with the low frequency sound attenuating Zone, said yopen areas in said gas passage means and intermediate shell forming acoustic couplings with the adjacent regions in the chamber, and an outlet pipe connected with said exhaust gas outlet for conveying exhaust gases from the chamber.

2. A mumer for blending exhaust gases of dual exhaust gas streams from dual manifolds of an internal combustion engine of an automotive vehicle, the combination of an elongated chamber having end closures, each of said end closures having an inlet, gas conveying pipes arranged to conduct exhaust gas streams from the engine into the chamber through the inlets in the end closures, a first walled gas passage means in said chamber in registration with said inlets adapted to receive the streams of gases entering the respective ends of the chamber whereby to blend the gases of `the streams, a second walled gas passage means in said chamber, one of said end closures having an outlet, exhaust gas discharge means connected with said outlet for conveying exhaust gases from the chamber, an intermediate shell surrounding said first gas passage means, the walls of said gas passage means and said intermediate shell being formed with a plurality of open areas to accommodate transverse fiow of gases from the first to the second gas passage means, annularly shaped means positioned within an-d spaced lengthwise of the intermediate shell forming a plurality of high frequency sound attenuating zones, a plurality of transversely arranged spaced walls in said chamber forming cornpartments through which gases flow from the first to the second gas passage means, each end closure forming with an adjacent transverse wall a low frequency sound attenuating zone, each of said low frequency sound attenuating zones being in communication with one of the gas passage means, said open areas in said gas passage means and intermediate shell forming acoustic couplings with the adjacent regions in the chamber.

3. A muffler for use with the exhaust gas streams from dual manifolds of an internal combustion engine of an automotive vehicle, the combination of an elongated chamber having end closures, each of said end closures being formed with an inlet, exhaust gas conveying tubes arranged to conduct exhaust gases from the manifolds through the inlet openings in the end closures into the chamber, a first tubular gas passage means in said chamber connected with said inlets adapted to receive the streams of gases entering the respective ends of the chamber whereby -to blend :the gases rof the streams, a second gas passage means in said chamber, outlet openings in said end closures in registry with the second tubular gas passage means, an intermediate shell surrounding said first gas passage means, the walls of said gas passage means and said intermediate shell being formed with a plurality of open yareas to accommodate transverse fiow of gases from the first -to the second gas passage means, a plurality of annular members positioned within and spaced lengthwise of the intermediate shell forming a plurali-ty of high frequency sound attenuating zones, a plurality of transversely arranged spaced walls in said chamber forming compartments through which gases flow from the first to the second gas passage means, one of said end closures forming with an adjacent wall a low frequency sound attenuating Zone, at lea-st one of said tubular gas passage means being in communication with the low frequency sound attenuating zone, said open areas in said gas passage means and intermediate shell forming acoustic couplings with the adjacent regions in the charnber, and pipes connected with the outlet openings in the end closures for discharging exhaust gases from the chamber.

4. A muier for use with multiple exhaust gas streams from dual exhaust manifolds of an internal combustion engine of a vehicle, in combination, lan elongated shell, end closures for the shell, `a first tubular gas passage means in said shell extending through openings in the end closures and adapted to receive from the manifolds exhaust gas streams moving in impinging relation in said means, lan intermediate shell surrounding the first -gas passage means, partition means between the intermediate shell and the first gas passage means defining `a plurality of high frequency sound attenuating chambers, a second tubular gas passage mean-s in said Ishell extending in substantial parallelism with said first gas passage means, at least one end of said second gas passage means cxtending through an end closure for discharging exhaust gases from the shell, a plurality of longitudinally spaced, transversely extending partitions in said shell forming a plunality of compartments, the walls of the tubular gas passage means and :said intermediate shell in the regions between adjacent partitions being formed with a plurality of small openings providing acoustic couplings with adjacent regions and facilitating transverse flow of gases from the first gas passage means to the second through the compartments, a tubular element in said shell extending between and in Comunication with end regions of the chamber and having imperforate walls, and an abutment in the central portion of the tubular element dividing the same into two low frequency resonator chambers.

5. A muffler for use with dual exhaust gas streams from dual manifolds of an internal combustion engine of a vehicle, in combination, an elongated shell adapted to be mounted transversely of the vehicle, end closures for the shell, a first gas passage tube in said shell extending full length of the shell and projecting into openings formed in the end closures and adapted to receive exhaust gas streams from the dual manifolds moving in impinging relation into both ends of said tube, a second gas passage tube in said shell extending in substantial parallel-ism with said first gas passage tube, at least one end of said second gas passage tube being in registration with ,an outlet opening in an end closure for discharging exhaust gases from the shell, a plurality of longitudinally spaced, transversely extending partitions 4in said `shell forming a plurality of compartments, the wall of both gas passage tubes adjacent compartments forrned by the partitions being provided with a plurality of small openings forming acoustic couplings with the compartments and providing for transverse iow of gases from the iirst gas passage tube to the second through the compartments, each end closure and the adjacent transversely extending Wall forming a low frequency sound attenuating chamber, each low frequency sound attenuating chamber being in communication with one of the gas passage tubes.

6. A muler for use with the exhaust gas streams from dual manifolds `of an internal combustion engine of a vehicle, in combination, yan elongated shell of generally oval cross-section, end closures for the shell, -a rst gas passage tube in said shell extending full length of the shell and projecting into openings formed in the end closures and adapted to receive from the manifolds exhaust :gas streams moving in impinging relation in said tube, an intermediate shell surrounding the rst gas passage tube, means between the intermediate shell and the first gas passage tube defining a plurality of high frequency sound attenuating chambers, a second gas passage tube in said shell extending in substantial parallelism with said irst gas passage tube, said second gas passage tube being in registration with outlet openings formed in the end closures, a plurality o longitudinally spaced, transversely extending partitions in said shell forming a plurality of compartments, the Walls of the gas passage tubes and said intermediate shell being formed with `a plurality of small openings forming acoustic couplings and providing for transverse flow of gases from the first gas passage tube to the second gas passage tube through the compartments, and pipes connected with the outlet openings in the end closures for conveying exhaust gases from the muffler.

References Cited in the file of this patent UNITED STATES PATENTS 2,026,795 Oldberg Jan. 7, 1936 2,078,420 Sheldrick Apr. 27, 1937 2,356,782 Muller Aug. 29, 1944 2,370,259 Rippingille Feb. 27, 1945 2,520,756 Bryant Aug. 29, 1950 2,658,580 'Trembley NOV. l0, 1953 2,661,073 Deremer Dec. l, 1953 2,692,025 Maxim Oct. 19, 1954 2,990,028 Powers June 27, 1961 

1. A MUFFLER FOR USE WITH THE EXHAUST GAS STREAMS FROM DUAL MANIFOLDS OF AN INTERNAL COMBUSTION ENGINE OF A VEHICLE, THE COMBINATION OF AN ELONGATED CHAMBER HAVING END CLOSURES, EACH OF SAID END CLOSURES HAVING AN INLET OPENING, EXHAUST GAS COVEYING PIPES CONNECTING THE EXHAUST MANIFOLDS WITH THE INLET OPENINGS ARRANGED TO CONDUCT STREAMS OF EXHAUST GASES FROM THE ENGINE THROUGH THE OPENINGS IN THE END CLOSURES INTO THE CHAMBER, A FIRST TUBULAR GAS PASSAGE MEANS IN SAID CHAMBER REGISTERING WITH SAID INLETS ADAPTED TO RECEIVE THE STREAMS OF GASES ENTERING THE RESPECTIVE ENDS OF THE CHAMBER WHEREBY TO BLEND THE GASES OF THE STREAMS, A SECOND TUBULAR GAS PASSAGE MEANS DISPOSED SUBSTANTIALLY PARALLEL WITH THE FIRST GAS PASSAGE MEANS IN SAID CHAMBER, AN EXHAUST GAS OUTLET IN REGISTRY WITH THE SECOND GAS PASSAGE MEANS, AN INTERMEDIATE SHELL SURROUNDING SAID FIRST GAS PASSAGE MEANS, THE WALLS OF THE TUBULAR GAS PASSAGE MEANS AND SAID INTERMEDIATE SHELL BEING FORMED WITH A PLURALITY OF OPEN AREAS 